Enzyme particles

ABSTRACT

Enzyme granules are provided in which an enzyme is rapidly eluted, without insoluble remnants, and generation of powdery dust is suppressed, and which granules have a property such that classification phenomenon generated among the granules in a detergent composition is less likely to take place, in a case where the enzyme granules are formulated together with other components in a detergent. The enzyme granule comprise (A) water-insoluble substance and or a slightly water-soluble substance; (B) a water-soluble binder; and (C) an enzyme. A dye may also be present for coloring. The content of (A) component is 45% by weight or more, and the enzyme granules have an average particle size of from 150 to 500 μm and a bulk density of from 500 to 1,000 g/L, and have a structure such that more amount of (B) component is present near the surface of the enzyme granules than in the inner portion thereof. The enzyme granule may be aggregated to form an enzyme granule aggregate. A process is provided for preparing the enzyme granule by spray-drying a slurry containing (A), (B) and (C). The enzyme granule aggregate may be prepared by adding an aqueous binding solution to the granules and drying, or by adding molten thermoplastic binder to the granules and cooling.

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/JP99/05555 which has an Internationalfiling date of Oct. 8, 1999, which designated the United States ofAmerica.

TECHNICAL FIELD

The present invention relates to enzyme granules suitably formulated ina detergent. Further, the present invention relates to a process forpreparing the enzyme granules. Further, the present invention relates toan enzyme granule aggregate suitably formulated in a detergent and aprocess for preparing the same.

BACKGROUND ART

In many cases, various enzymes are formulated in detergents such aslaundry powder detergents, powder bleaching agents and powder detergentsfor automatic dishwashing machines for the purpose of enhancing theirdetergency.

Since an enzyme exhibits its effects for the first time after dissolvingin water, the enzyme has such a property that a certain amount of timeis required before exhibiting its effect. Therefore, in order tooptimally exhibit the performance of the enzyme, whether or not theenzyme granules have a property of quickly eluting an enzyme from enzymegranules (referred to as “fast dissolubility”) is important. Especiallyregarding the laundry detergents, and the like, its importance is evenmore increasing under the present situation of the tendency of shortenedwashing time.

Further, in a case where the formulation to a detergent is considered,when there are insoluble remnants of the enzyme granules at thetermination of washing, there arises a problem such as deposition of theinsoluble remnant components to washing items. Therefore, it isimportant that all of the substances constituting the enzyme granulesare dispersed within a washing period, thereby preventing to haveinsoluble remnants.

In addition, in order to secure safety of the working environment, it isimportant to suppress the amount of powdery dusts generated from theenzyme granules (referred to as “amount of dusts generated”).

Further, in a case where after-blending to the detergent is considered,it is desired that the enzyme granules are homogeneously distributed inthe detergent from the viewpoint of quality. In order to achieve this,it is important to prevent the classification of the enzyme granuleswith other granules constituting the detergent by approximating theparticle size and the bulk density of the enzyme granules to those ofthe other granules. In addition, in consideration of externalappearance, the larger the particle size, the more desirable, from theviewpoint of the visual confirmability, and the lower the bulk density,the more desirable, from the viewpoint of the number of granules.

In consideration of these viewpoints, there is becoming increasinglyimportant a technique satisfying the fast dissolubility and the low dustgenerating property, properties required regardless of being formulatedin a detergent composition, and also being capable of controlling aparticle size and a bulk density, properties becoming important whenformulated in a detergent, to match those of the detergent.

However, these properties are closely related to each other. Forinstance, while the dissolubility is improved by making the particlesize small, the amount of dusts generated tends to increase at the sametime. While the amount of dusts generated is lowered by increasing thebulk density, the dissolubility tends to be lowered at the same time.Therefore, it has been conventionally difficult to obtain enzymegranules satisfying these required properties at the same time.

For instance, Japanese Examined Patent Publication No. Sho 50-22506discloses a process for preparing a microcapsule comprising an enzymefor detergents, comprising spray-drying a solution comprising the enzymefor detergents and an inorganic salt being copresent in a water-solublebinder solution, or a dispersion thereof. While the microcapsuleactually prepared which has a particle size in a range of from 20 to 130μm can be thought to satisfy excellent dissolubility when formulated ina detergent to be used, it is difficult to suppress the classificationphenomenon caused among the granules, because the particle size isextremely small as compared to the detergent. In addition, in the enzymegranules obtainable by this technique, since the content of thewater-soluble substance is substantially large, the enzyme granules havea hollow structure having a weak strength, so that it is difficult tosuppress the amount of dusts generated, and thereby the requiredproperties described above for an enzyme could not be satisfied at thesame time.

Japanese Patent Laid-Open No. Hei 7-289259 discloses a process forpreparing enzyme granules for detergents, comprising subjecting amixture comprising an enzyme for detergents and aluminosilicate powderto agitation and tumbling granulation using a water-soluble organicbinder. According to this process, a problem regarding the suppressionof the amount of dusts generated is solved by carrying out granulation.However, it is difficult to satisfy the fast dissolubility owing to anincrease in the particle size and the compression of the granules duringgranulation, and thereby the required properties described above for anenzyme could not be satisfied at the same time even by this process.

An object of the present invention is to provide enzyme granules inwhich an enzyme is rapidly eluted, without insoluble remnants, and thegeneration of the powdery dusts is suppressed, thereby having a propertysuch that classification phenomenon generated among the granules in thedetergent composition is less likely to take place (referred to as“non-classifiable property”), in a case where the enzyme granules areformulated in a detergent together with other components. A furtherobject of the present invention is to provide a process for preparingthe enzyme granules. A still another object is to provide an enzymegranule aggregate in which an enzyme is rapidly eluted, withoutinsoluble remnants, and the generation of the powdery dusts issuppressed, thereby having a non-classifiable property, in a case wherethe enzyme granules are formulated in a detergent together with othercomponents, by aggregating enzyme granules having structure such thatmore amount of a water-soluble binder is present near the surface of theenzyme granules than the inner portion thereof. A still another objectis to provide a process capable of suitably preparing an enzyme granuleaggregate. These objects and other objects of the present invention willbe apparent from the following description.

DISCLOSURE OF INVENTION

Specifically, the present invention relates to:

[1] enzyme granules comprising (A) a water-insoluble substance and/or aslightly water-soluble substance; (B) a water-soluble binder; and (C) anenzyme, wherein the content of (A) component is 45% by weight or more,and wherein the enzyme granules have an average particle size of from150 to 500 μm and a bulk density of from 500 to 1,000 g/L, and have astructure such that more amount of (B) component is present near thesurface of the enzyme granules than in the inner portion thereof;

[2] a process for preparing the enzyme granules of item [1], comprisingspray-drying a slurry comprising (A) a water-insoluble substance and/ora slightly water-soluble substance; (B) a water-soluble binder; and (C)an enzyme at a temperature so as not to substantially deactivate theenzyme, to give the enzyme granules;

[3] an enzyme granule aggregate comprising enzyme granules comprising(A) a water-insoluble substance and/or a slightly water-solublesubstance; (B) a water-soluble binder; and (C) an enzyme, wherein theenzyme granules have a structure such that more amount of (B) componentis present near the surface of the enzyme granules than in the innerportion thereof; and

[4] a process for preparing an enzyme granule aggregate, comprisingadding water or an aqueous binder solution to enzyme granules, dryingand/or cooling the resulting mixture, the enzyme granules comprising (A)a water-insoluble substance and/or a slightly water-soluble substance;(B) a water-soluble binder; and (C) an enzyme, wherein the enzymegranules have a structure such that more amount of (B) component ispresent near the surface of the enzyme granules than in the innerportion thereof; or comprising adding a molten thermoplastic binder tothe enzyme granules and cooling the resulting mixture, thereby givingthe enzyme granule aggregate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing the construction of a rotatabledustmeter used for determination of the amount of dusts generated in thepresent invention. An upper view of FIG. 1 is a front view, and a lowerview is a cross-sectional view taken along the line A—A, respectively. 1is a pulverizing ball, 3 is a filter, 4 is an inlet for introducing air,5 is an outlet for discharging air, and 6 is a rotatable shaft,respectively.

FIG. 2 is a graph showing the measurement results obtained by FT-IR/PASof the enzyme granules obtained in Example 3. An arrow in the figureindicates the position of a peak for the water-soluble binder. 11 isdata for those near the surface of the granules, and 12 is data forthose in the inner portion thereof.

FIG. 3 is a graph showing the measurement results obtained by FT-IR/PASof the enzyme granules obtained in Example 10. An arrow in the figureindicates the position of a peak for the water-soluble binder. 11 isdata for those near the surface of the granules, and 12 is data forthose in the inner portion thereof.

BEST MODE FOR CARRYING OUT THE INVENTION 1. (A) Component

The water-insoluble substance or water slightly soluble substance of (A)component usable in the present invention is not particularly limited,as long as the substance does not exhibit dissolubility in water, orslightly exhibit dissolubility, the substance capable of exhibitingproperties of having substantially no deactivation of an enzyme, beingunreactive with a water-soluble binder, and being dispersible in water.The substance may be an inorganic substance or organic substance, andthe inorganic substance is more preferable, from the viewpoint that thehigher the stability against heat, the more advantageous, in a casewhere a process requiring heat, such as spray-drying, is employed.Concrete examples of (A) component include cellulose powder, zeolites,talc, clay, alumina, kaolin, titania, calcium carbonate, barium sulfate,and the like, and zeolite and kaolin, which are excellent in thedispersibility in water, are especially preferable.

As to the size of (A) component used, it is preferable that an averageparticle size of the primary granules is 20 μm or less, from theviewpoint of the homogeneity of the distribution in the inner portion ofthe enzyme granules. In addition, the average particle size of theprimary granules of (A) component is more preferably 10 μm or less,particularly preferably from 0.1 to 5 μm, from the viewpoints that thesmaller the average particle size of the primary granules, the morecompressed the enzyme granules become, so that the granule strength isimproved owing to the compression, and thereby the dust generatingproperty can be suppressed.

The content of (A) component in the enzyme granules is preferably 45% byweight or more of the enzyme granules, from the viewpoints ofsuppressing the generation of powdery dusts, giving breakdown anddispersibility in the enzyme granules, and promoting rapid elution ofthe enzyme, and the content is more preferably 50% by weight or more,from the viewpoint of further enhancing the fast dissolubility. On theother hand, the content is preferably 90% by weight or less, morepreferably 80% by weight or less, particularly preferably 70% by weightor less, of the enzyme granules, from the viewpoints of suppressing theamount of dusts generated and preventing insoluble remnants. Therefore,in consideration of satisfying the fast dissolubility and the low dustgenerating property at the same time and preventing insoluble remnants,the content is preferably from 45 to 90% by weight or more, morepreferably from 50 to 90% by weight, still more preferably from 50 to80% by weight, particularly preferably from 50 to 70% by weight, of theenzyme granules.

In addition, in the present invention, (A) component may be each usedalone, or in combination of both substances. Also, in a case where twoor more kinds of (A) component are used in combination, the structure ofthe enzyme granules can be compressed or reinforced by formulatinggranules having different particle sizes or particles having differentmorphologies, whereby the dust generating property can be suppressed.

For instance, in a case where granules having an average particle sizeof the primary granules of from 2 to 3 μm are used in combination withgranules having an average particle size of the primary granules of 1 μmor less, the suppression of dust generation can be achieved, as comparedto a case where granules having an average particle size of the primarygranules of from 2 to 3 μm are used alone. As described above, in a casewhere granules having different particle sizes are used in combination,although the proportion of the granules having smaller particle sizes isnot particularly limited, the proportion is preferably from 5 to 60% byweight, more preferably from 5 to 50% by weight, of (A) component, fromthe viewpoint of an effect of suppression of dust generation.

2. (B) Component

The water-soluble binder of (B) component usable in the presentinvention is not particularly limited, as long as the substance iscapable of binding the components constituting the granules themselves,the substance capable of exhibiting properties of having substantiallyno deactivation of an enzyme and being rapidly dissolving in water.Examples thereof include polyethylene glycols, polypropylene glycols,polyoxyethylene alkyl ethers and their derivatives, polyvinyl alcoholsand their derivatives, water-soluble cellulose derivatives (thederivatives thereof include ether compounds, and the like), carboxylatepolymers, starches, saccharides, and the like. The carboxylate polymersand the saccharides are preferable from the viewpoints of theproductivity and the fast dissolubility, and salts of acrylicacid-maleic acid copolymers and polyacrylates are more preferable. Thesalts are preferably sodium salts, potassium salts and ammonium salts.Here, the molecular weight of the carboxylate polymer is preferably from1,000 to 100,000, more preferably from 2,000 to 80,000.

The content of (B) component in the enzyme granules is preferably 5% byweight or more, more preferably 15% by weight or more, of the enzymegranules, from the viewpoint of the low dust generating property. Thecontent is preferably 40% by weight or less, more preferably 30% byweight or less, of the enzyme granules, from the viewpoint of the fastdissolubility. Therefore, from the viewpoints of the low dust generatingproperty and the fast dissolubility, the content is preferably from 5 to40% by weight, more preferably from 15 to 30% by weight, of the enzymegranules.

In addition, the water-soluble binders used in the present invention canbe formulated in combination of two or more kinds as occasion demands. Acompound effect can be expected by combining water-soluble bindershaving two or more kinds of different effects. For instance, thestability of the enzyme granules can be further imparted by using abinder having stabilization ability of the enzyme in combination with abinder capable of rapidly dissolving in water.

3. (C) Component

The enzyme of (C) component usable in the present invention is notparticularly limited, as long as the enzyme is capable of exhibitingsuch effects as detergency, when formulated in a detergent. Forinstance, there can be preferably used one or more kinds selected fromcellulase, protease, pectinase, amylase, lipase, and dextranase.

The content of the enzyme in the enzyme granules is preferably 0.5% byweight or more, more preferably 2% by weight or more, from the viewpointof the exhibition of an enzyme activity. The content is preferably 30%by weight or less, more preferably 25% by weight or less, from theviewpoint of the fast dissolubility. Therefore, from the viewpoints ofthe exhibition of an enzyme activity and the fast dissolubility, thecontent is preferably from 0.5 to 30% by weight, more preferably from 2to 25% by weight.

As the form of the enzyme used, for instance, the enzyme may be used inthe form of a concentrate prepared by filtering a culture comprising anenzyme produced by a microorganism and concentrating the culture, or inthe form of an enzyme powder obtained by drying the concentrate. When anenzyme concentrate is used, the saccharides, inorganic salts, and thelike, which cannot be separated by filtration may be contained in theconcentrate.

4. (D) Component

The dye of (D) component usable in the present invention is notparticularly limited, as long as the dye has high dissolubility. Thehigher the stability against heat, the more preferable, in a case wherea process requiring heat, such as spray-drying, is employed. Concreteexamples thereof are Red No. 106, Red No. 227, Blue No. 1, Blue No. 2,Green No. 3, Yellow No. 203, and the like. The content of these dyes ispreferably 0.001% by weight or more of the enzyme granules, from theviewpoint of the coloring ability, and the content is preferably 1.0% byweight or less of the enzyme granules, from the viewpoint of thedispersibility of the dye. More preferably, the content is from 0.01 to0.5% by weight of the enzyme granules. In addition, in the presentinvention, two or more kinds of dyes may be used in admixture. Theadjustment of hue can be readily achieved by mixing two or more kinds ofdyes.

5. Other Water-Soluble Substances

The enzyme granules of the present invention may comprise otherwater-soluble substances, besides (A) component, (B) component, and (C)component mentioned above, as occasion demands. For instance, there canbe formulated as a stabilizing agent or an excipient, sodium chloride,calcium chloride, magnesium chloride, sodium sulfate, and the like. Theamount of the other water-soluble substance is preferably such that atotal sum of the contents of the enzyme, the water-soluble binder andthe water-soluble substances is in a range of not exceeding 55% byweight of the enzyme granules. Especially, from the viewpoint of thefast dissolubility and the low dust generating property, the content ofthe other water-soluble substances is preferably 15% by weight or less,more preferably 10% by weight or less, of the enzyme granules.

A preferable combination of (A) component, (B) component, and the otherwater-soluble substances includes, for instance, zeolite as (A)component, a sodium polyacrylate and a saccharide as (B) components, andan excipient sodium sulfate as the other water-soluble substances.

6. Enzyme Granules of Present Invention

There are two embodiments for the enzyme granules of the presentinvention in accordance with the ranges of their average particle sizes.The enzyme granules of Embodiment 1 of the present invention have anaverage particle size of from 150 to 500 μm, and in order to suitablysatisfy the fast dissolubility, the low dust generating property and thenon-classifiable property, the average particle size is preferably from200 to 400 μm. The average particle size may be adjusted, for instance,by sieving and separating the enzyme granules after preparation.

The average particle size of the enzyme granules of Embodiment 2 of thepresent invention is not particularly limited, because the optimalparticle size varies depending upon the average particle size of thetargeted enzyme granule aggregate. The average particle size ispreferably 500 μm or less, more preferably 300 μm or less, from theviewpoint of the fast dissolubility. In addition, the average particlesize is preferably 100 μm or more, more preferably 150 μm or more, fromthe viewpoint of the suppression of dust generation. Therefore, from theviewpoints of the fast dissolubility and the suppression of dustgeneration, the average particle size is preferably from 100 to 500 μm,more preferably from 100 to 300 μm, particularly preferably from 150 to300 μm.

In addition, the enzyme granules comprising granules having a size offrom 125 to 710 μm in an amount of 80% by weight or more are preferable,and those enzyme granules comprising such particles in an amount of 90%by weight or more of the entire granules are preferable, from theviewpoints of the dust generating property and the dissolubility.Further, from the viewpoint of the non-classifiable property, it ispreferable that the particle size distribution is as homogeneous aspossible.

Also, the bulk density of the enzyme granules is preferably from 500 to1000 g/L or more, from the viewpoint of the non-classifiable property.The water content value of the enzyme granules in the present inventionis preferably 10% by weight or less, more preferably 5% by weight orless, from the viewpoint of quality.

The enzyme granules of the present invention have a structure such thatmore amount of the water-soluble binder of (B) component is present nearthe surface of the enzyme granules than in the inner portion thereof.Since the water-soluble binder is localized near the surface asdescribed above, the water-soluble binder is firstly dissolved in water,and thereafter water contacts with (A) component, so that the granulesthemselves undergo breakdown and disperse in water, whereby the enzymein water is rapidly eluted. Therefore, as long as the enzyme granuleshave the above structure, the enzyme can be rapidly eluted even when theparticle size or the bulk density becomes large, so that the insolubleremnants would be little. In addition, since the amount of the bindercapable of binding the components constituting the granules themselvesis large near the surface of the enzyme granules, the granule strengthis further improved, whereby the low dust generating property can berealized.

The localized structure of the water-soluble binder can be confirmed bythe following method.

First, there are prepared enzyme granules to be measured and apulverized product of enzyme granules prepared by sufficientlypulverizing the enzyme granules in an agate mortar or the like, to be ina homogeneous state. Thereafter, the structures of both the enzymegranules and the pulverized product of enzyme granules are measured by acombined method of Fourier transform infrared spectroscopy (FT-IR) andphotoacoustic spectroscopy (PAS) [referred to as “FT-IR/PAS”], under theconditions that information up to a depth of about 10 μm from thesurface of the enzyme granules and the pulverized product of enzymegranules is obtained. In a case where the amount of the water-solublebinder of the former is greater than the amount of the water-solublebinder of the latter, the enzyme granules to be measured have astructure such that more amount of the water-soluble binder is presentnear the surface of the enzyme granules than in the inner portionthereof.

The measurement conditions for obtaining information up to a depth ofabout 10 μm from the surface of the enzyme granules and the pulverizedproduct of enzyme granules include, for instance, resolution of 8 cm⁻¹,scanning speed of 0.63 cm/s, and 128 scans. The measurement device usedincludes, for instance, an infrared spectrometer “Model FTS-60A/896”manufactured by Bio-Rad Laboratories, and the PAS cell includes anacoustic detector “Model 300” manufactured by MTEC Corporation.Incidentally, “FT-IR/PAS” is described in “APPLIED SPECTROSCOPY 47,1311-1316 (1993).

As mentioned above, the enzyme granules of the present invention areuseful because the enzyme rapidly elutes with no insoluble remnants, thegeneration of powdery dusts is suppressed, and the granules exhibitnon-classifiable ability.

In addition, the enzyme granules are preferably colored with a dye, fromthe viewpoint of obtaining acceptable appearance. The enzyme granulesobtainable by spray-drying the slurry comprising a dye have a structuresuch that more amount of the dye is present near the surface of theenzyme granules than in the inner portion thereof. The enzyme granuleshaving this structure are more vivid than those having a structure suchthat the dye is substantially homogenously dispersed in the entiregranules, and this structure can be confirmed by slicing the enzymegranules, and observing its cross section.

7. Process for Preparing Enzyme Granules of Present Invention

It is desired that the process for preparing the enzyme granules of thepresent invention is, for instance, a process comprising spray-drying aslurry comprising (A) component, (B) component and (C) component, inorder to prevent the lowering of the dissolubility owing to thecompression of the enzyme granules. In addition, in order to obtaingranules having a structure such that more amount of the water-solublebinder is present near the surface of the enzyme granules than in theinner portion thereof, there are, for instance, a process comprisingpreparing granules by drying the above slurry, and thereaftersurface-coating the granule surface with a water-soluble binder; aprocess comprising spray-drying the above slurry, and the like.Especially, during heating and drying, since more amount of thewater-soluble binder is collected near the surface of the granules alongwith the migration of water, a spray-drying process capable of easilyobtaining granules having the above-mentioned structure is preferable.

When the enzyme granules of the present invention are prepared byspray-drying process, first, a slurry comprising each of the componentsis prepared. The content of each of the components for the resultingenzyme granules corresponds to the content of each of the components inthe solid ingredients of the slurry. In the present specification, theterm “solid ingredients” refers to (A) component, (B) component, (C)component, and other water-soluble substances.

In addition, as a dispersion medium for the preparation of the slurry,water is usually used.

It is preferable to increase the content of the solid ingredients of theslurry for spray-drying, because the dust generating property of theresulting enzyme granules can be lowered. In consideration of satisfyingboth the fast dissolubility and the low dust generation, the content ofthe solid ingredients is preferably 40% by weight or more, morepreferably 50% by weight or more, of the slurry. In addition, from theviewpoint of ease in slurry spraying, the content of the solidingredients is preferably 60% by weight or less. Therefore, the contentof the solid ingredients is preferably from 40 to 60% by weight, morepreferably from 50 to 60% by weight, of the slurry.

The order of formulation of (A) component, (B) component, and (C)component when the spray-dried slurry is prepared is not particularlylimited. Since there is an optimal order from the viewpoints of theadjustment of slurry formulation and the dust generating property andsuch an order differs depending upon the properties of the formulatedsubstances, an order can be appropriately optimized. For instance, in acase where zeolite is used as (A) component, a sodium polyacrylate and asaccharide are used as (B) components, and sodium sulfate is used as anexcipient, it is preferable to formulate in the order of an enzyme,sodium sulfate, a saccharide, zeolite, and a sodium polyacrylate.

The prepared slurry is fed to a spray-drying device. The temperature forthe slurry during feeding is preferably a temperature such that anenzyme is not substantially deactivated. From the viewpoints of thestability of the enzyme and the ease in the preparation of the slurry,the temperature is preferably from 10° to 40° C., more preferably from20° to 30° C.

The air-blow temperature during spray-drying is preferably from 120° to220° C., more preferably from 140° to 180° C. It is preferable to carryout spray-drying in this temperature range, because the productivitybecomes excellent, and the enzyme is not substantially deactivated.

In addition, in the enzyme granules of Embodiment 1, for the purposes ofdecreasing the amount of dusts generated and improving the storagestability of the enzyme granules obtained by spray-drying, the surfaceof the above granules may be coated by using a coating agent comprisingcomponents which do not lose the dissolubility of the above granules.The coating agent includes water-soluble, thermoplastic substances, andconcrete examples are polyethylene glycols and their derivatives, fattyacids, and the like (derivatives include ether compounds and the like).Especially, the polyethylene glycols and their derivatives arepreferable, and those having a molecular weight of from 2000 to 10000 orso are more preferable.

A concrete coating operation includes, for instance, an embodiment ofheat-fusing these coating agents, and coating and depositing on thesurface of the spray-dried granules.

The enzyme granules of the present invention may be colored. The processfor coloring the enzyme granules is not particularly limited, and it ispreferable to use a dye rather than a pigment, from the viewpoints ofsuppressing dye-transfer to components other than the enzyme granulesand to the granules, and staining ability to garments, and the like.

A process for coloring with a dye includes, for instance, a processcomprising coating enzyme granules with a coating agent comprising a dyedispersed therein, to give colored enzyme granules; a process comprisingspraying an aqueous solution prepared by dispersing a dye and a coatingagent in enzyme granules to coat the granules, with subjecting theenzyme granules to fluidization and drying, to give colored enzymegranules; and a process comprising drying a slurry comprising (A) awater-insoluble substance and/or water-slightly soluble substance, (B) awater-soluble binder, (C) an enzyme, and (D) a dye, to give coloredenzyme granules. Among them, a process comprising drying the slurry, togive colored enzyme granules, is preferable. In this process, since thedye is formulated in the slurry, the dye can be easily and homogeneouslydispersed in the slurry, and as a result, granules having high coloringability of the dye can be obtained. A process comprising spray-dryingthe slurry comprising a dye at a temperature in which the enzyme is notsubstantially deactivated, to give colored enzyme granules is especiallypreferable. By this process, the resulting granules have a structuresuch that more amounts of the water-soluble binder and the dye arepresent near the surface thereof. Therefore, the dye-transfer tocomponents other than the enzyme granules or to the granules can besuppressed by this process, whereby enzyme granules having moreexcellent coloring ability can be obtained.

8. Enzyme Granule Aggregate

The enzyme granule aggregate comprising the enzyme granules may have astructure such that the enzyme granules are aggregated, and its processfor aggregation is not limited. From the viewpoints of the stability ofthe aggregated structure and the productivity, an enzyme granuleaggregate in which the enzyme granules are aggregated by a binder[hereinafter referred to as “(E) component] is preferable.

This enzyme granule aggregate comprises a structure such that several toseveral dozens of enzyme granules are bound to each other, withretaining the original shape and structure of the enzyme granules. Sincethe enzyme granules are aggregated without being compressed, the enzymegranules undergo breakdown and disperse in water as in the case of asingle enzyme granule, whereby the enzyme in water is rapidly eluted,without losing the fast dissolubility owned by the enzyme granules. Inaddition, since the improvement in particle sizes is caused byaggregation, the dust generating property owned by the enzyme granulescan be further suppressed.

The average particle size of the enzyme granule aggregate is preferably150 μm or more, more preferably 200 μm or more, particularly preferably300 μm or more, from the viewpoint of the visual confirmability. Also,the average particle size is preferably 2000 μm or less, more preferably1000 μm or less, particularly preferably 700 μm or less, from theviewpoint of the suppression of classification. Therefore, from theviewpoints of the visual confirmability and the suppression ofclassification, the average particle size is preferably from 150 to 2000μm, more preferably from 200 to 1000 μm, still more preferably from 300to 1000 μm, particularly preferably from 300 to 700 μm.

The average particle size of the enzyme granule aggregate can becontrolled by the average particle size of the enzyme granules and theconditions for aggregation. For instance, if the average particle sizeof the enzyme granules is made small under the same aggregationconditions, the average particle size of the enzyme granule aggregatebecomes small. In addition, when the enzyme granules having the sameaverage particle size are used, if the forming rate of aggregation isincreased, the average particle size of the enzyme granule aggregatebecomes large.

Likewise, the bulk density can be also controlled by the averageparticle size of the enzyme granules and the conditions for aggregation.For instance, granules having a low bulk density can be obtained bymaking the particle size of the enzyme granules small and looselyaggregating the enzyme granules.

From the above, as to the classification during blending the enzymegranule aggregate in the detergent composition, the classification canbe suppressed by controlling the average particle size and the bulkdensity of the aggregate. For instance, such an enzyme granule aggregatecan be widely formulated, for instance, from detergent compositionshaving a low bulk density such as conventional detergents to detergentcompositions having a high bulk density such as compact-type detergents.

The shape of the enzyme granule aggregate is not particularly limited.For instance, the classification in the detergent can be furthersuppressed by having an irregular shape.

In order that the enzyme granule aggregate has a fast dissolubility, theenzyme granules themselves must have fast dissolubility. In addition,since the dust generating property of the enzyme granule aggregate ishighly influenced by the generated dusts of the enzyme granules, it isdesirable that the dust generating property of the enzyme granules issuppressed as much as possible.

When the enzyme granules are aggregated by (E) component in the presentinvention, (E) component is not particularly limited as long as it hasan ability of binding the enzyme granules with each other and does notsubstantially deactivate an enzyme. (E) component may be the same one asthat for (B) component, or those other than (B) component or (B)component which is present in more amount near the surface of the enzymegranules may be used. In addition, (E) component may be water-insolubleor water-soluble, and two or more kinds may be used in combination.

It is preferable that at least one kind of (E) component iswater-soluble, from the viewpoint of the fast dissolubility. Inaddition, when only water-insoluble (E) component is used, it ispreferable that (E) component easily allows penetration of water intothe surface of the enzyme granules in water, without completely coatingthe surface of the enzyme granules, from the viewpoint of the fastdissolubility.

The water-insoluble (E) component includes, for instance, fatty acids,higher alcohols, cured oils, and the like. The water-soluble (E)component includes, for instance, polyethylene glycols, polypropyleneglycols, polyoxyethylene alkyl ethers and derivatives thereof, polyvinylalcohols and derivatives thereof, polyvinyl pyrrolidones, water-solublecellulose derivatives (their derivatives include ether compounds, andthe like), carboxylate polymers, starches, saccharides, and the like.The polyethylene glycols and their derivatives are preferable, from theviewpoints of the fast dissolubility and the low dust generatingproperty. The polyethylene glycols have a molecular weight of preferablyfrom 3000 to 30000, and more preferably from 5000 to 15000.

Also, the enzyme granule aggregate may further comprise other substancesas occasion demands, besides the enzyme granules and (E) componentmentioned above. The other substances contained in the enzyme granuleaggregate are not particularly limited, as long as the fastdissolubility of the enzyme granule aggregate is not lost. The enzymegranule aggregate may be used in combination of two or more kinds. Forinstance, for the purpose of adjusting a bulk density, there can beformulated sodium chloride, calcium chloride, magnesium chloride, sodiumsulfate, and the like.

9. Process for Preparing Enzyme Granule Aggregate

A process for preparing an enzyme granule aggregate include (1) aprocess comprising adding water or an aqueous solution containing (E)component to the enzyme granules of Embodiment 2, and drying and/orcooling the mixture, to give an enzyme granule aggregate; (2) a processcomprising adding a molten thermoplastic (E) component to the enzymegranules, and cooling the mixture, to give an enzyme granule aggregate;and the like. The process (1) is preferable, from the viewpoints of thefast dissolubility and the productivity.

Among the process (1), embodiments for adding water are:

(i) a process comprising spraying water with drying the enzyme granules,thereby partially dissolving (B) component on the surface of the enzymegranules to deposit and aggregate thereon, and thereafter further dryingthe product;

(ii) a process in a case where enzyme granules are prepared byspray-drying a slurry, comprising stopping drying of the enzyme granulesat a water content of 10% by weight or more, thereafter partiallydissolving (B) component on the surface of the enzyme granules by suchsteps as allowing to stand or fluidizing the enzyme granules, depositingand aggregating the enzyme granules, and thereafter drying theaggregate; and the like.

Among the process (1), an embodiment for adding an aqueous solutioncontaining (E) component includes:

(iii)a process comprising spraying (E) component in the form of anaqueous solution with drying enzyme granules, thereby depositing andaggregating with (B) component on the enzyme granule surface partiallydissolved with the aqueous solution, and sprayed (E) component, andthereafter further drying and/or cooling the product; and the like. Theprocess of (iii) is preferable, from the viewpoints of the suppressionof dust generation and the particle size control.

The process (2) includes:

(iv) a process comprising spraying a molten thermoplastic (E) componentwith fluidizing the enzyme granules, depositing these components on theenzyme granule surface, solidifying (E) component by cooling, andaggregating the granules; and the like.

The aggregation operation is not particularly limited, as long as theenzyme granules are deposited and aggregated with suppressing thecompression of the enzyme granules. The aggregation operation includes,for instance, a process comprising depositing and aggregating byallowing to stand the granules or by fluidizing the granules. Amongthem, the deposition and aggregation by fluidizing the granules arepreferable, from the viewpoints of the particle size control and theproductivity.

The process for fluidization includes, for instance, a process offluidizing by an agitation and tumbling granulator, or by a fluidizedbed, and the like. From the viewpoint of the particle size control, theprocess by the fluidized bed is preferable.

Therefore, as the process for preparing an enzyme granule aggregate, aprocess comprising spraying (E) component in the form of an aqueoussolution with fluidizing and drying the enzyme granules, therebydepositing and aggregating (B) component on the surface of the enzymegranules partially dissolved with an aqueous solution, and the sprayed(E) component, and thereafter further drying the aggregate, ispreferable, from the viewpoint of the suppression of dust generated, theparticle size control, and the productivity. A process comprisingspraying (E) component in the form of an aqueous solution withfluidizing and drying the enzyme granules by using a fluidized bed,thereby depositing and aggregating (B) component on the surface of theenzyme granules partially dissolved with an aqueous solution, and thesprayed (E) component, and thereafter further drying the aggregate, ismore preferable, from the viewpoints of the suppression of the dustsgenerated and the particle size control.

When the enzyme granule aggregate is prepared by the above process (1),the drying temperature is not particularly limited, as long as it is atemperature where the enzyme is not substantially deactivated. Thehigher the drying temperature, the better, from the viewpoint of theproductivity, and the drying temperature is preferably 30° C. or more,preferably 50° C. or more. On the other hand, the lower the dryingtemperature, the better, from the viewpoint of the enzyme activity, andthe drying temperature is 100° C. or less, more preferably 70° C. orless. Therefore, the drying temperature is preferably from 30° to 100°C., more preferably from 50° to 70° C., from the viewpoints of theproductivity and the enzyme activity.

In addition, when an enzyme granule aggregate is prepared by the aboveprocess (1), in a case where a thermoplastic substance such as apolyethylene glycol is selected as (E) component, it is preferable thatdrying is carried out at a melting temperature for (E) component orlower, from the viewpoint of the suppression of the deposition to theinner portion of the mixer.

(E) component usable for aggregation of the enzyme granules includesthose listed in Section 8. above. In addition, the amount of (E)component added is not particularly limited, and it may not be addedwhen (B) is used therefor, and the like. When (E) component is added,the amount may be preferably 20% by weight or less, more preferably 10%by weight or less, particularly preferably 5% by weight or less, of theenzyme granule aggregate, from the viewpoint of the fast dissolubility.On the other hand, the amount is preferably 1% by weight or more, morepreferably 3% by weight or more, from the viewpoint of the low dustgenerating property. Therefore, the amount is preferably from 1 to 20%by weight, more preferably from 1 to 10% by weight, still morepreferably from 3 to 5% by weight, of the enzyme granule aggregate, fromthe viewpoints of the fast dissolubility and the low dust generatingproperty. In addition, when (E) component is used in the form of anaqueous solution, (E) component may be water-soluble or water-insoluble.It is preferable that (E) component is dissolved or homogeneouslydispersed, from the viewpoint of the dispersibility in the enzymegranules. The concentration of (E) component is preferably from 5 to 60%by weight, more preferably from 10 to 50% by weight, from the viewpointof the dispersibility in the enzyme granules.

10. Coloring of Enzyme Granule Aggregate

The enzyme granule aggregate may be colored. It is preferable to use adye rather than a pigment from the viewpoints of suppressingdye-transfer to components other than the enzyme granule aggregate andto the granules, and suppressing staining ability to garments, and thelike.

The process for coloring with a dye includes, for instance, a processcomprising depositing and aggregating the granules using (E) componentcomprising a dye dispersed therein, to give colored enzyme granuleaggregate; a process comprising spraying an aqueous solution prepared bydispersing a dye and (E) component to coat the granules, with subjectingthe enzyme granules to fluidization and drying, to give a colored enzymegranule aggregate; and a process of preparing enzyme granules preparedby drying a slurry comprising (A) component, (B) component and (C)component, the process comprising formulating a dye in a slurry, andcoloring the enzyme granules, thereby giving a colored enzyme granuleaggregate. The process comprising drying a slurry formulated with a dye,and coloring the enzyme, thereby giving a colored enzyme granuleaggregate, is preferable. In this process, since the dye is formulatedin a slurry, the dye can be easily homogenously dispersed in the slurry,and consequently, the granules having high coloring ability of the dyecan be obtained. A process comprising spray-drying a slurry comprising adye at a temperature where the enzyme is not substantially deactivated,and coloring the enzyme granules, to give a colored enzyme granuleaggregate, is particularly preferable. By this process, the resultingenzyme granules and the enzyme granule aggregate have a structure suchthat more amounts of the water-soluble binder and the dye are presentnear the surface thereof. Therefore, the dye-transfer to the componentsother than the enzyme granule aggregate and the granules is suppressedby this process, whereby an enzyme granule aggregate having moreexcellent coloring ability can be obtained.

The usable dye is not particularly limited, as long as it is a substancehaving a high dissolubility in water. The dye may be any ones, and in acase where the dye is used in a preparation process requiring heat suchas spray-drying, those having high stability against heat arepreferable. As the dye, there can be used Red No. 106, Red No. 227, BlueNo. 1, Blue No. 2, Green No. 3, Yellow No. 203, and the like. The amountof the dye formulated is preferably 0.01% by weight or more to theenzyme granules, from the viewpoint of the coloring ability. Inaddition, the amount is preferably 1.0% by weight or less, morepreferably from 0.001 to 0.5% by weight or less, of the enzyme granules,from the viewpoint of the dispersibility of the dye.

In addition, in the present invention, two or more kinds of dyes may beused. The hue can be easily adjusted by mixing two or more kinds ofdyes.

The fast dissolubility, the low dust generating property, the averageparticle size, the bulk density, the non-classifiable property, and thestaining ability in the present invention are measured by the followingmethods.

[Fast Dissolubility]

In the present invention, the term “enzyme granules having fastdissolubility” refers to those enzyme granules having an elution rate of70% or more and a dissolution rate of 85% or more. The elution ratecorresponds to a time period until an enzyme is eluted from the enzymegranules to exhibit their performance, and the dissolution ratecorresponds to a degree of prevention of insoluble remnants,respectively. The enzyme granules satisfying the fast dissolubility arevery highly preferable because the enzymes rapidly act and at the sametime there are no insoluble remnants.

The elution rate of an enzyme was calculated as follows.

A 100 mL beaker (inner diameter: 105 mm) was charged with 100 mg ofenzyme granules, and 100 mL of water at 20° C. having a water hardnessof 4° DH was poured thereinto. The mixture was stirred with a magneticstirrer (length: 35 mm, diameter: 8 mm) (200 r.p.m.), to give an enzymesolution. The value calculated by the equation (1) was defined as anelution rate of the enzyme for this enzyme solution. $\begin{matrix}{\text{Elution Rate (\%)} = \frac{\left\lbrack {A \times 100} \right\rbrack}{B}} & (1)\end{matrix}$

wherein A: an enzyme activity value for the enzyme solution obtained bystirring under above stirring conditions for 30 seconds; and

B: an enzyme activity value indicating a constant value when the anenzyme activity value for the enzyme solution was assayed with thepassage of time under above stirring conditions.

Incidentally, as to the assay for the enzyme activity value, an assaysuitable for each enzyme may be employed.

For instance, in the case of a cellulase, the following CMC activityassay can be employed. To a substrate solution comprising 0.4 mL of anaqueous solution of 2.5% by weight carboxymethyl cellulose (CMC), 0.2 mLof 0.5 M glycine buffer (pH 9.0), and 0.3 mL of deionized water wasadded 0.1 mL of an enzyme solution, and mixed, and the resulting liquidmixture was incubated at 40° C. for 20 minutes. Next, the deoxysaccharide was quantified by utilizing the following3,5-dinitrosalicylic acid (DNS) method. Specifically, 1 mL of a DNSreagent was added to 1 mL of the liquid mixture after incubation, andthe liquid mixture was heated at 100° C. for 5 minutes. Subsequently,after cooling the liquid mixture, 4 mL of deionized water was addedthereto to dilute the solution. Thereafter, the absorbance wasdetermined at 535 nm to quantify the deoxy saccharide. In the case ofassaying under these conditions, an amount of an enzyme capable ofreleasing 1 μmol of a deoxy saccharide, calculated on the basis ofglucose, in one minute is defined as one unit.

In addition, in the case of a protease, the following casein method canbe employed. One milliliter of 50 mM borate-sodium hydroxide buffer (pH10.0) containing 1% by weight of casein was mixed with 0.1 mL of anenzyme solution, and the liquid mixture was incubated at 40° C. for 10minutes. Next, 2 mL of a reaction-stopper solution (0.123 Mtrichloroacetic acid-0.246 M sodium acetate-0.369 M acetic acid) wasadded to this liquid mixture, and the mixture was incubated at 30° C.for 20 minutes. Subsequently, the resulting liquid was filtered using afilter paper (manufactured by Whatman, No. 2), and the proteindegradation product in the filtrate was assayed by improved Folin-Loewymethod. In the case of assaying under these conditions, an amount of anenzyme capable of releasing 1 mmol of tyrosine in one minute was definedas one unit.

The dissolution rate of the enzyme granules was calculated as follows.

A 1 L beaker (inner diameter: 105 mm) was charged with 1 L of water at5° C. having a water hardness of 4°DH, and 1 g of enzyme granules wereadded thereto. The mixture was stirred with a magnetic stirrer (length:35 mm, diameter: 8 mm) (800 r.p.m.) for 60 seconds. The value calculatedby the equation (2) was defined as a dissolution rate of the enzymegranules for the resulting aqueous solution. $\begin{matrix}{\text{Dissolution Rate (\%)} = {\left\{ {1 - \frac{D}{C}} \right\} \times 100}} & (2)\end{matrix}$

wherein C: weight (g) of the enzyme granules supplied; and

D: dry weight (g) of enzyme granules remaining on a sieve after sievingthe aqueous solution obtained under the above stirring conditions usinga standard sieve (sieve-opening: 74 μm) according to JIS Z 8801 [dryingconditions: keeping at a temperature of 105° C. for one hour, andthereafter keeping in a desiccator (25° C.) containing a silica geltherein for 30 minutes].

[Low Dust Generating Property]

The term “low dust generating property” in the present invention refersto those having an amount of dusts generated of 1000 mg or less. Thelower the amount of dusts generated, the more desirable, and the amountof dusts generated is more preferably 500 mg or less, still morepreferably 100 mg or less. In addition, the standard value for theamount of dusts generated also varies depending upon the kinds of theenzymes. For instance, it is preferable that the amount of dustsgenerated, such as protease which greatly affects the human bodies, ispreferably 100 mg or less, more preferably 20 mg or less.

Here, the term “amount of dusts generated” is assayed as follows. Withrotating the pulverization balls at a rotational speed of 44 r.p.m., 20g of the enzyme granules were placed in a rotatable dustmeter capable ofpassing a dry air at 20 L/min from an air introducing inlet 4 to an airdischarging outlet 5 and capturing in a filter 3 granules carried alongthe air flow in the upper convergent part, the rotatable dustmetercomprising a cylinder having a diameter of 6.0 cm of which upper end wasconverged and 4 pulverization balls 1 incorporated therein each having adiameter of 2.0 cm and a weight of 32.2 g. The amount of dusts generatedis defined as an amount of powdery dusts when carrying out a 20 minutesdetermination therewith. As the filter 3, one having a diameter of 5.0cm, a size of captured particles of 0.5 μm, and a pressure loss of 0.42kPa when an air flow rate was 5 cm/s was used.

The rotatable dustmeter used for the determination is not particularlylimited. As this dustmeter, a rotatable dustmeter having such astructure as shown in FIG. 1, for instance, one made commerciallyavailable by Heubach GmbH, Dustmeter TYPE. III, can be used.

[Average Particle Size]

The average particle size was measured by vibrating each of standardsieves according to JIS Z 8801 for 5 minutes, and calculating the sizefrom a weight percentage depending upon the sieve-openings of thesieves.

[Bulk Density]

The bulk density was measured by a method according to JIS K 3362.

[Non-Classifiable Property]

In Examples 1 to 6 and Comparative Example 1, the following operationswere carried out.

One gram of the colored enzyme granules were blended with 100 g ofdetergent granules (average particle size: 400 μm, bulk density: 750g/L), and thereafter vibration was applied to the mixture with a mixer.Whether or not classification was generated was determined visually.

In Examples 7 to 15 and Comparative Examples 2 and 3, the followingoperations were carried out.

Six grams of the colored enzyme granules were blended with 594 g of adetergent composition (average particle size: 400 μm, bulk density: 750g/L), and thereafter the mixture was packed in a container (length: 9cm, width: 15 cm, and height: 11 cm) and then sealed. The sealedcontainer was loaded on a carrier of a truck, and transported for 1000km. Thereafter, the seal was opened, and the presence or absence ofclassification generation was determined visually.

[Staining Ability]

The amount 0.1 g of the colored enzyme granules were blended with 10 gof detergent granules (average particle size: 400 μm, bulk density: 750g/L). A test cloth (25×16 cm) was spread over a vat, and water at 20° C.having water hardness of 4°DH was poured into the vat until the testcloth was soaked. Next, the blend of the enzyme granules and thedetergent granules was evenly sprinkled on the test cloth. A separatetest cloth was further overlaid on the test cloth, and water was furtherpoured gently to a level where an entire cloth was soaked. Thereafter,it was allowed to stand overnight, with maintaining the room temperatureat 30° C. After rinsing the test cloth, the test cloth was press-dried.Whether or not stained garment was generated on the dried test cloth wasdetermined visually. As the test cloths, those made of the polyester andcotton were used.

EXAMPLE 1

A spray-dried slurry having a content of solid ingredients of 45% byweight was prepared from the raw materials shown in Table 1 and water.The spray-dried slurry was sprayed at a spraying pressure of 2.5 MPausing a pressure-type spray nozzle. The slurry was spray-dried by usinga counter current spray-drying tower (diameter: 3 m, tower height: 10 m)at an air-blow rate of 100 m³/min, an air-blow temperature of 150° C., aslurry spraying rate of 200 kg/Hr. From the resulting granules, thegranules having a size of 1410 μm or more were removed using a sieve, togive enzyme granules having a water content value of 4.1% by weight.

TABLE 1 Composition (% by weight) Example Example Example Example Comp.1 2 3 4 Ex. 1 (A) Zeolite*⁴ 70 35 65 30   39.5 Kaolin*⁵ — 35 — 30 — (B)Sodium — — — 15 11 Polyacrylate*¹ Sodium 12 12 — — — Polyacrylate*²Sodium Salt of — —   12.5 — — Acrylic Acid- Maleic Acid Copolymer*³Saccharide 12 12   12.5 — 11 (C) Cellulase  6  6  4 —   5.5 Protease — —— 20 — Other Water- Soluble Substance Sodium Sulfate — —  6  5 33*¹Completely neutralized product, molecular weight: 10000 *²Completelyneutralized product, molecular weight: 20000 *³Degree of neutralization:0.8, molecular weight: 30000 *⁴Average primary particle size: 3.0 μm*⁵Average primary particle size: 0.4 μm

Incidentally, in Table 1, “Cellulase” is an alkali cellulase disclosedin Japanese Patent Laid-Open No. Hei 6-343461, and “Protease” is ALKALIPROTEASE K-16 disclosed in Japanese Patent Laid-Open No. Hei 5-25492. Asthe saccharide, Maltorich (“MR-25” manufactured by Showa SangyoKabushiki Kaisha) was used.

EXAMPLE 2

A spray-dried slurry having a content of solid ingredients of 45% byweight was prepared from the raw materials shown in Table 1 and water.The slurry was subjected to spray-drying and sieving under the sameconditions as in Example 1, to give enzyme granules having a watercontent value of 4.5% by weight.

EXAMPLE 3

A spray-dried slurry having a content of solid ingredients of 55% byweight was prepared from the raw materials shown in Table 1 and water.The slurry was subjected to spray-drying and sieving under the sameconditions as in Example 1, to give enzyme granules having a watercontent value of 3.4% by weight.

EXAMPLE 4

A spray-dried slurry having a content of solid ingredients of 50% byweight was prepared from the raw materials shown in Table 1 and water.The slurry was subjected to spray-drying under the same conditions as inExample 1. Subsequently, granules having a size of 125 μm or less andgranules having a size of 710 μm or more were removed using a sieve, togive enzyme granules having a water content value of 3.8% by weight.

EXAMPLE 5

In an agitation and tumbling granulator (High-Speed Mixer manufacturedby Fukae Powtec Corp., Model “FS-10”) of which jacket warm water at 60°C. flowed through were supplied 5.0 kg of the enzyme granules obtainedin Example 4, and stirred at a rotational speed of the main axis of 240r.p.m., and a rotational speed of disintegrating impellers at 2700r.p.m. With stirring, 250 g of a polyethylene glycol (molecular weight:6000) melted at 80° C. was supplied as a coating agent. After supplyingthe coating agent, the mixture was stirred for 10 minutes to allowsurface coating of the granules. From the resulting granules, granuleshaving a size of 1410 μm or more were removed using a sieve, to giveenzyme granules having a water content value of 3.1% by weight.

The elution rate, the dissolution rate, the average particle size, thebulk density, the amount of dusts generated, and the non-classifiableproperty of the enzyme granules obtained in Example 1 to 5 are shown inTable 2. All of these granules satisfied the required properties, andthe enzyme granules were excellent in the fast dissolubility, thesuppression of the amount of dusts generated, and the non-classifiableproperty. As a result of measuring each of these enzyme granules inaccordance with the FT-IR/PAS described above, it was confirmed that allof these enzyme granules have localized structure such that thewater-soluble binder exists more near the surface than in the innerportion thereof. FIG. 2 shows the measurement results for the enzymegranules obtained in Example 3 in accordance with FT-IR/PAS.

COMPARATIVE EXAMPLE 1

A spray-dried slurry having a content of solid ingredients of 55% byweight was prepared from the raw materials shown in Table 1 and water.The slurry was subjected to spray-drying and sieving under the sameconditions as in Example 1, to give enzyme granules having a watercontent value of 4.3% by weight. The elution rate, the dissolution rate,the average particle size, the bulk density, the amount of dustsgenerated, and the non-classifiable property of the resulting enzymegranules are shown in Table 2.

EXAMPLE 6

A slurry was prepared by formulating 0.2 parts by weight of a dye BlueNo. 1, based on 100 parts by weight of the solid ingredients of theslurry, in the composition of Example 1 during the preparation of theslurry. The slurry was subjected to spray-drying and sieving under thesame conditions as in Example 1, to give enzyme granules which wereuniformly colored in blue. The elution rate, the dissolution rate, theaverage particle size, the bulk density, the amount of dusts generated,and the non-classifiable property of the resulting enzyme granules weresubstantially the same as those of the enzyme granules in Example 1. Nostaining ability was observed in the enzyme granules. In addition, theenzyme granules were formulated in a detergent composition, and thedye-transfer was examined. As a result, no dye-transfer was found in theenzyme granules.

TABLE 2 Example Example Example Example Example Comparative 1 2 3 4 5Example 1 Elution Rate (%) 98.5 95.4 91.1 100.0 97.7 98.5 DissolutionRate (%) 99.6 99.0 98.0 99.7 99.1 99.8 Average Particle Size (μm) 164169 246 204 207 271 Bulk Density (g/L) 757 921 779 830 801 562 Amount ofDusts Generated 493.0 146.7 133.9 62.0 13.0 1286.8 (mg) Presence ofClassification None None None None None None Generation(Non-Classifiable Property)

EXAMPLE 7

A spray-dried slurry having a content of solid ingredients of 55% byweight was prepared from the raw materials shown in Table 3 and water.The spray-dried slurry was sprayed at a spraying pressure of 2.5 MPausing a pressure-type spray nozzle. The slurry was spray-dried by usinga counter current spray-drying tower (diameter: 3 m, tower height: 10 m)at an air-blow rate of 100 m³/min, an air-blow temperature of 150° C., aslurry spraying rate of 200 kg/Hr. From the resulting granules, thegranules having a size of 1410 μm or more were removed using a sieve, togive enzyme granules having a water content value of 4.2% by weight.

With fluidizing and drying 0.96 kg of the enzyme granules in a fluidizedbed (bottom area: 0.19 m² and tower height: 1 m) at an air-blow rate of60 m³/Hr and an air-blow temperature of 60° C., 200 g of water wassprayed from an upper powder layer at a rate of 15 g/min. Aftertermination of spraying, the granules were dried for 10 minutes, to givean enzyme granule aggregate. Incidentally, in Table 3, “Cellulase” is analkali cellulase disclosed in Japanese Patent Laid-Open No. Hei6-343461, and “Protease” is ALKALI PROTEASE K-16 disclosed in JapanesePatent Laid-Open No. Hei 5-25492. As the saccharide, Maltorich (“MR-25”manufactured by Showa Sangyo Kabushiki Kaisha) was used.

EXAMPLE 8

with fluidizing and drying 0.96 kg of the enzyme granules of Example 7using a fluidizing bed (the same apparatus and the same conditions), anaqueous solution prepared by dissolving 40 g of a polyethylene glycol(molecular weight: 6000) in 160 g of water was sprayed from an upperpowder layer at a rate of 15 g/min. After the termination of spraying,the granules were dried for 10 minutes, and then cooled to ordinarytemperature, to give an enzyme granule aggregate.

EXAMPLE 9

With fluidizing 0.96 kg of the enzyme granules of Example 7 using afluidizing bed (the same apparatus and the same conditions), a liquid ina melting state prepared by heating 40 g of a polyethylene glycol(molecular weight: 6000) to 80° C. was sprayed from an upper powderlayer at a rate of 3 g/min. After the termination of spraying, thegranules were cooled to ordinary temperature, to give an enzyme granuleaggregate.

EXAMPLE 10

A spray-dried slurry having a content of solid ingredients of 50% byweight was prepared from the raw materials shown in Table 3 and water.The slurry was spray-dried under the same conditions as in Example 7,except that a slurry spraying rate was 180 kg/Hr. Subsequently, granuleshaving a size of 1410 μm or more were removed using a sieve, to giveenzyme granules having a water content value of 4.5% by weight.

With fluidizing and drying 0.95 kg of the resulting enzyme granulesusing a fluidizing bed (bottom area: 0.19 m² and tower height: 1 m) atan air-blow rate of 60 m³/Hr and an air-blow temperature of 60° C., anaqueous solution prepared by dissolving 50 g of a polyethylene glycol(molecular weight: 6000) in 117 g of water was sprayed from a bottompowder layer at a rate of 10 g/min. After the termination of spraying,the granules were dried for 10 minutes, to give an enzyme granuleaggregate.

EXAMPLE 11

A spray-dried slurry having a content of solid ingredients of 45% byweight was prepared from the raw materials shown in Table 3 and water.The slurry was spray-dried under the same conditions as in Example 7,except that a slurry spraying rate was 160 kg/Hr. Subsequently, granuleshaving a size of 1410 μm or more were removed using a sieve, to giveenzyme granules having a water content value of 3.4% by weight.

With fluidizing and drying 0.95 kg of the resulting enzyme granulesusing a fluidizing bed (bottom area: 0.19 m² and tower height: 1 m) atan air-blow rate of 60 m³/Hr and an air-blow temperature of 60° C., anaqueous solution prepared by dissolving 50 g of a polyethylene glycol(molecular weight: 6000) in 200 g of water was sprayed from an upperpowder layer at a rate of 15 g/min. After the termination of spraying,the granules were dried for 10 minutes, to give an enzyme granuleaggregate.

EXAMPLE 12

A spray-dried slurry having a content of solid ingredients of 55% byweight was prepared from the raw materials shown in Table 3 and water,and the slurry was spray-dried under the same conditions as in Example7. Subsequently, granules having a size of 1410 μm or more were removedusing a sieve, to give enzyme granules having a water content value of4.3% by weight.

With fluidizing and drying 0.95 kg of the resulting enzyme granulesusing a fluidizing bed (bottom area: 0.19 m² and tower height: 1 m) atan air-blow rate of 60 m³/Hr and an air-blow temperature of 60° C., anaqueous solution prepared by dissolving 50 g of a polyethylene glycol(molecular weight: 6000) in 117 g of water was sprayed from a bottompowder layer at a rate of 10 g/min. After the termination of spraying,the granules were dried for 10 minutes, to give an enzyme granuleaggregate.

TABLE 3 Composition (% by weight) Examples Examples Example 7-9 10-11 12(A) Zeolite*¹ 70 60   39.5 (B) Sodium — 15 11 Polyacrylate*² Sodium 12 —— Polyacrylate*³ Saccharide 12 — 11 (C) Cellulase  6 —   5.5 Protease —20 — Other Water-Soluble Substance Sodium Sulfate —  5 33 *¹Averageprimary particle size: 3.0 μm *²Completely neutralized product,molecular weight: 10000 *³Completely neutralized product, molecularweight: 20000

The elution rate, the dissolution rate, the average particle size, thebulk density, the amount of dusts generated, and the non-classifiableproperty of the enzyme granule aggregates obtained in Examples 7 to 12are shown in Table 4. The inventive products were enzyme granuleaggregates excellent in the fast dissolubility, suppression of theamount of dusts generated, and the non-classifiable property. As aresult of measuring each of these enzyme granules in accordance withFT-IR/PAS described above, it was confirmed that all of these enzymegranules have localized structure such that (B) component exists morenear the surface than in the inner portion thereof. FIG. 3 shows themeasurement results for the enzyme granules obtained in Example 10 inaccordance with FT-IR/PAS.

EXAMPLE 13

The elution rate, the dissolution rate, the average particle size, thebulk density, the amount of dusts generated, and the non-classifiableproperty of the enzyme granules obtained in Example 7 before aggregationare shown in Table 4.

EXAMPLE 14

The elution rate, the dissolution rate, the average particle size, thebulk density, the amount of dusts generated, and the non-classifiableproperty of the enzyme granules obtained in Example 10 beforeaggregation are shown in Table 4.

COMPARATIVE EXAMPLE 2

The elution rate, the dissolution rate, the average particle size, thebulk density, the amount of dusts generated, and the non-classifiableproperty of the enzyme granules obtained in Example 11 beforeaggregation are shown in Table 4.

COMPARATIVE EXAMPLE 3

The elution rate, the dissolution rate, the average particle size, thebulk density, the amount of dusts generated, and the non-classifiableproperty of the enzyme granules obtained in Example 12 beforeaggregation are shown in Table 4.

TABLE 4 Comparative Examples Examples 7 8 9 10 11 12 13 14 2 3 ElutionRate (%) 97.3 95.2 96.5 98.2 97.5 98.5 98.4 99.0 99.2 98.5 DissolutionRate 99.2 99.3 99.0 99.7 99.2 99.0 99.8 99.8 99.8 99.8 (%) AverageParticle 398 402 432 384 310 395 252 246 141 271 Size (μm) Bulk Density566 552 537 608 595 505 716 775 803 562 (g/L) Amount of Dusts 106 51 7242 292 475 279 255 1503 1287 Generated (mg) Presence of None None NoneNone None None None None Present None Classification Generation

EXAMPLE 15

A slurry was prepared by formulating 0.1 parts by weight of a dye BlueNo. 1, based on 100 parts by weight of the solid ingredients of theslurry, in the composition of Example 8 during the preparation of theslurry. The slurry was subjected to spray-drying and aggregationoperation under the same conditions as in Example 8, to give an enzymegranule aggregate which was uniformly colored in blue. The elution rate,the dissolution rate, of the average particle size, the bulk density,the amount of dusts generated, and the non-classifiable property of theresulting enzyme granule aggregate were substantially the same as thoseof the enzyme granule aggregate in Example 8. No staining ability wasobserved in the enzyme granules. In addition, the enzyme granuleaggregate was formulated in a detergent composition, and thedye-transfer was examined. As a result, no dye-transfer was also foundin the enzyme granule aggregate.

INDUSTRIAL APPLICABILITY

According to the present invention, there is provided enzyme granuleswhich exhibit such effects as the fast dissolubility, the suppression ofdust generation, and non-classifiable ability. Further, according to thepresent invention, when the enzyme granules are colored with a dye,there can be provided enzyme granules with suppressed staining abilityagainst fibers and suppressed dye-transfer against detergent granules.Further, according to the present invention, there is provided an enzymegranule aggregate which exhibits such effects as the fast dissolubility,the suppression of dust generation, and non-classifiable ability.

EQUIVALENT

Those skilled in the art will recognize, or be able to ascertain usingsimple routine experimentation, many equivalents to the specificembodiments of the invention described in the present specification.Such equivalents are intended to be encompassed in the scope of thepresent invention described in the following claims.

What is claimed is:
 1. Enzyme granules comprising (A) a water-insolublesubstance and/or a slightly water-soluble substance; (B) a water-solublebinder; and (C) an enzyme, wherein the content of said (A) component is45% by weight or more, and wherein the enzyme granules have an averageparticle size of from 150 to 500 μm and a bulk density of from 500 to1,000 g/L, and have a structure such that more amount of said (B)component is present near the surface of the enzyme granules than in theinner portion thereof.
 2. The enzyme granules according to claim 1,wherein the content of (B) component is from 5 to 40% by weight.
 3. Theenzyme granules according to claim 1, which are colored with a dye. 4.The enzyme granules according to claim 3, wherein more amount of dye ispresent near the surface of the enzyme granules than in the innerportion thereof.
 5. A process for preparing the enzyme granules of claim1, comprising spray-drying a slurry comprising (A) the water-insolublesubstance and/or a slightly water-soluble substance; (B) thewater-soluble binder; and (C) the enzyme at a temperature so as not tosubstantially deactivate the enzyme, to give the enzyme granules.
 6. Aprocess for preparing the enzyme granules of claim 3, comprisingspray-drying a slurry comprising (A) the water-insoluble substanceand/or a slightly water-soluble substance; (B) the water-soluble binder;(C) the enzyme; and (D) the dye at a temperature so as not tosubstantially deactivate the enzyme, to give the enzyme granules.
 7. Theprocess according to claim 5, wherein the content of solid ingredientsin the slurry is from 40 to 60% by weight.